


Oh My God, They Were Roommates

by CasualCazz



Category: Undertale (Video Game)
Genre: Alternate Universe - Swapfell, Alternate Universe - Underswap, College AU, Frottage, M/M, Sanscest - Freeform, Somnophilia, Swapfell Sans, Underswap Sans
Language: English
Status: Completed
Published: 2018-06-13
Updated: 2018-06-13
Packaged: 2019-05-21 17:23:07
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 576
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14919662
Author URL: https://archiveofourown.org/users/CasualCazz/pseuds/CasualCazz
Summary: Black is pent up from his studying, but good thing his roommate is there to help him.





	Oh My God, They Were Roommates

**Author's Note:**

> [ Follow my Tumblr for earlier updates ](http://www.casualbones.tumblr)
> 
>  
> 
> I wanted to write something short, and my significant other wanted something with Rottenberry so here we are. I hope you guys enjoy!

Blue snores softly on his bed across the room, stirring occasionally and mumbling in his sleep. Black sighs in annoyance and tosses his pencil on the table, his table light the only thing illuminating the dark dorm room. He doesn’t understand how his roomate can spend finals week sleeping, but then again, Blue and Black are both closely ranked at the top of their classes. Unable to study with the distraction, he shoves his books and supplies into his bag and turns off his light, coating the dorm room in darkness. Black makes his way to the door, but pauses, noticing a light blue glow in the corner of his eye. He glances over, and blushes, eyeing the raging boner poking from Blue’s shorts. It’s not the first time he’s seen this of course, they are roommates after all and have needs, but his breath hitches, and he drops his bag. He couldn’t stop himself from walking over and carefully crawling on top of his roomate, the bed sinking upon his impression. Blue continues to sleep soundly, unaware of Black’s strange actions.

Maybe it’s the stress, but the skeleton doesn’t try to rationalize it. He hypnotically stares at the glow, and before he could stop himself, he strokes the dick, gasping at the firmness and the warmth flowing into his fingers. Blue stirs and moans, but doesn’t wake. Black’s own bulge forms throbbing in heat. Lingering in lusty haze, Black mounts his roomate, swinging Blue’s leg over his shoulder and he presses his boner against the other’s, their clothing the only barrier. He leans forward, Black’s face only itches away from Blue’s and thrusts, stiffling his whimpers. Wetness pools out of both of their pants, their pre mingingling with each other in salty goodness.

Black picks up his pace, dry humping his roommate without a care in the world. Blue stays asleep, but even so, Black notices the shifts of pleasure, his mouth parting in quiet gasps, his eyes squinting together harder in ecstasy. Black’s tongue lolls out, the pressure inside building further and further. He tugs on his scarf and cut of his airway, his head getting lighter by the second.

“fuck me blue!” Black whispers loudly, the heat in between his pants nearly at its limit, “fuck this dirty slut!”

Seconds later, cum guzzles out of his dick, creaming both of their pants. A dark stain forms on Black’s crotch that dribbles down to Blue’s. With his head more clear, he finally realized what he did and immediately jumps off of him. His roommate moans and shifts onto his stomach, curling into a ball, but stays asleep. Black sighs in relief, changes his pants, grabs his bag, and leaves immediately, too flustered to face what happened.

Hours later, Black comes back to his dorm, with the lights on and Blue changing into his gym clothes.

“HEYA BLACK! HOW WAS STUDYING?!” Blue asks cheerfully.

“I JUST FOUND OUT HOW TO CALCULATE THE TRAJECTORY OF A SPACECRAFT FLYING OVER A DWARF STAR. I’D SAY IT WENT WELL,” Black chuckles and brags, but unable to meet Blue in the eyes.

“I’M PROUD THAT YOU LEARNED SOMETHING!” Blue embraces Black from behind, his strong arms keeping Black from jumping in surprise. He leans in close, hands cupping Black’s crotch seductively, “Maybe when I get back, you can teach me something too. Dirty slut,”

Blue disappears a moment later, while Black’s cheek’s heat up. Great. He’s already hard again.


End file.
